chengji = int(input('请输入你的成绩'))

# 判断
if 90 <= chengji <= 100:
    print('A级')
elif 80 <= chengji <= 89:
    print('B级')
elif 70 <= chengji <= 79:
    print('C级')
elif 60 <= chengji < 69:
    print('D级')
elif 0 <= chengji < 59:
    print('E级')
else:
    print('您输入的成绩有误')
